The first units, called type A12117c, are produced in an adjacent department. Historically (แต่เดีม), these parts have been produced at a rate of 12 per hour, but the actual flow is not at all steady. (Because time is short, the adjacent department itself will not be modeled.) The proposal calls for these parts to have their own preparation area (หรือเรียกว่า “prep area”). At the prep area for A12117c, the mating faces of the cases will be machined to insure a good seal, and then deburred and cleaned. A factory worker who used to do this kind of job at another plant thinks it will take about 4 minutes per part, with a range of 1 to 8 minutes. The A12117c parts will then be transferred to the insertion/sealing/inspection operation.
At the insertion/sealing/inspection operation (มีสถานีเดียวสาหรับทั้ง A12117c และ B33433x) the electronic components are inserted, the case is assembled and sealed, and the completed unit is tested. The time to accomplish all of this is expected to be 2 minutes for the A12117c assemblies, and 3 minutes for the B33433x assemblies. An average variation of plus-or-minus 20% around these values is considered the standard allowance for variability.